プラスチック射出成形におけるウェルドラインと型締力最小化のためのプロセスパラメータの最適化

抄録

Weldlines are one of the major defects in plastic injection molding (PIM). The weldlines have an influence on not only the strength of product but also the appearance, so it is important to reduce the weldlines as much as possible. The melt plastic will be quickly solidified with the low weldline temperature, that makes the weldlines long. Then, we consider that the weldline temperature will be an important factor for the weldlines reduction. Clamping force also affect the product quality, but the relationship between the weldlines and the clamping force is rarely discussed in the literature. In this paper, the minimum weldline temperature is maximized for the weldlines reduction, whereas the clamping force is minimized for the high product quality. Therefore, a multi-objective design optimization is performed and the pareto-frontier between them is identified. Numerical simulation in PIM is generally so intensive that a sequential approximate optimization (SAO) using a radial basis function (RBF) network is used to identify the pareto-frontier. Through the numerical simulation, the trade-off between the minimum weldline temperature and the clamping force is clarified. Based on the numerical result, the experiment is carried out in order to examine the validity of the proposed approach. Through numerical and experimental result, the validity of the proposed approach is confirmed.